There are generally two methods used for searching for items within a collection of information, such as a database containing multiple information sources such as text documents. The first method commonly is called a Boolean search which performs logical operations over items in the collection according to rules of logic. Such searching uses conventional logic operations, such as "and", "or" or "not," and perhaps some additional operators which imply ordering or word proximity or the like or have normative force. Another method is based on a statistical analysis to determine the apparent importance of the searched terms within individual items. The search terms accrue "importance" value based on a number of factors, such as their position in an item and the context in which they appear. For example, a search term appearing in the title of a document may be given more weight than if the search term appears in a footnote of the same document. There are several forms, variations and combinations of statistical and Boolean searching methods.
One problem with searching large collections of information of many items (e.g., records, text documents, etc.) is that a particular query may provide search results which include items irrelevant to what the framer of the search has in mind or items which are too numerous for all to be reviewed. Using a large public computer network like the Internet to search a database of information available on the network, search results may be too numerous or of little value to the user and the search engine may be very frustrating to use. While the search results may be presented in an order according to some rule, such as by displaying the newest item first, by placing the items in alphabetical order, or by ranking the items according to some score assigned to the item, most search engines do not provide the capability for a user to control how search results are presented to a user or, at best, allow only minimal control in a manner that actually changes the query performed and hence affects the search results.